Ultrasound catheter apparatus

ABSTRACT

Ultrasound catheter devices and methods of the present invention generally provide for ablation and/or disruption of vascular occlusions. An ultrasound transmission member, such as a wire, transmits vibrational energy from an ultrasound transducer to a distal head of the catheter to disrupt vascular occlusions. At least one absorber member is disposed on or around the ultrasound transmission wire at a location adjacent the sonic connector of the catheter. The absorber member absorbs heat, vibrations, and/or the like from the ultrasound transmission wire at or near the area where the transmission wire is coupled with the sonic connector. The absorptive function typically slows the process of wear and tear on the transmission wire, thus extending the useful life of the ultrasound catheter.

This application is a division of U.S. patent application Ser. No.10/375,903 (Attorney Docket No. 021577-000700US), filed Feb. 26, 2003,and is related to pending U.S. patent application Ser. No. 10/229,371,filed Aug. 26, 2002, entitled “Ultrasound Catheter for Disrupting BloodVessel Obstructions,” (Attorney Docket No. 21577-000400US) the fulldisclosures of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates generally to medical devices and methods.More specifically, the present invention relates to ultrasound catheterdevices and methods for treating occlusive intravascular lesions.

Catheters employing various types of ultrasound transmitting membershave been successfully used to ablate or otherwise disrupt obstructionsin blood vessels. Specifically, ablation of atherosclerotic plaque orthromboembolic obstructions from peripheral blood vessels such as thefemoral arteries has been particularly successful. Various ultrasoniccatheter devices have been developed for use in ablating or otherwiseremoving obstructive material from blood vessels. For example, U.S. Pat.Nos. 5,267,954 and 5,380,274, issued to an inventor of the presentinvention and hereby incorporated by reference, describe ultrasoundcatheter devices for removing occlusions. Other examples of ultrasonicablation devices for removing obstructions from blood vessels includethose described in U.S. Pat. Nos. 3,433,226 (Boyd), 3,823,717 (Pohlman,et al.), 4,808,153 (Parisi), 4,936,281 (Stasz), 3,565,062 (Kuris),4,924,863 (Sterzer), 4,870,953 (Don Michael, et al), and 4,920,954(Alliger, et al.), as well as other patent publications W087-05739(Cooper), W089-06515 (Bernstein, et al.), W090-0130 (Sonic NeedleCorp.), EP, EP316789 (Don Michael, et al.), DE3,821,836 (Schubert) andDE2438648 (Pohlman). While many ultrasound catheters have beendeveloped, however, improvements are still being pursued.

Typically, an ultrasonic catheter system for ablating occlusive materialincludes three basic components: an ultrasound generator, an ultrasoundtransducer, and an ultrasound catheter. The generator converts linepower into a high frequency current that is delivered to the transducer.The transducer contains piezoelectric crystals which, when excited bythe high frequency current, expand and contract at high frequency. Thesesmall, high-frequency expansions and contractions have both longitudinaland transverse components (relative to an axis of the transducer and thecatheter), which are amplified by the transducer horn into vibrationalenergy. The vibrations are then transmitted from the transducer throughthe ultrasound catheter via an ultrasound transmission member (or wire)running longitudinally through the catheter. The transmission membertransmits the vibrational energy to the distal end of the catheter wherethe energy is used to ablate or otherwise disrupt a vascularobstruction.

To effectively reach various sites for treatment of intravascularocclusions, ultrasound catheters of the type described above typicallyhave lengths of about 150 cm or longer. To permit the advancement ofsuch ultrasound catheters through small and/or tortuous blood vesselssuch as the aortic arch, coronary vessels, and peripheral vasculature ofthe lower extremities, the catheters (and their respective ultrasoundtransmission wires) must typically be sufficiently small and flexible.Due to attenuation of ultrasound energy along the long, thin, ultrasoundtransmission wire, a sufficient amount of vibrational energy must beapplied at the proximal end of the wire to provide a desired amount ofenergy at the distal end.

An ultrasound transmission wire is usually coupled at its proximal endwith the transducer by means of a sonic connector. The sonic connectortypically has a significantly larger diameter than that of theultrasound transmission member, the difference in diameters helping toamplify the vibrational energy being transmitted from the transducer tothe transmission wire. This amplification of vibrations, however,creates stress and heat in the transmission wire in an area adjacent itsconnection with the sonic connector. Stress and heat generated by theseamplified vibrations (especially transverse vibrations) significantlyreduce the usable life of the ultrasound transmission wire and may causeits premature breakage at or near the point of contact with the sonicconnector.

Efforts have been made to reduce transverse vibrations somewhere alongthe length of an ultrasound transmission member. For example, U.S. Pat.Nos. 5,382,228 and 6,494,891, both of which issued to an inventor of thepresent invention and are hereby incorporated by reference, describemechanisms for absorbing transverse motion of an ultrasound transmissionwire. Currently available devices and devices described in the abovepatents, however, to not reduce stress and/or heat in an ultrasoundtransmission wire at or near its point of contact with a sonic connectoras much as may be desired. As just discussed, this proximal area of thetransmission wire may be one of the most vulnerable areas due to itsexposure to amplified vibrational energy from the sonic connector.

Therefore, a need exists for an improved ultrasound catheter device andmethod that provides ablation or disruption of vascular occlusions.Ideally, the ultrasound catheter would include means for reducing heatin the ultrasound transmission wire component of the catheter at or nearits coupling with the sonic connector component. Alternatively oradditionally, it would also be ideal if transverse vibrations and stresswere reduced in a proximal portion of the transmission wire. Suchcatheter devices would ideally be sufficiently thin and flexible to beadvanced through narrow, tortuous vasculature, such as the coronaryvasculature, while also being configured to enhance the usable life ofthe ultrasound transmission wire. At least some of these objectives willbe met by the present invention.

BRIEF SUMMARY OF THE INVENTION

Ultrasound catheter devices and methods of the present inventiongenerally provide for ablation and/or disruption of vascular occlusions.An ultrasound transmission member, such as a wire, transmits vibrationalenergy from an ultrasound transducer to a distal head of the catheter todisrupt vascular occlusions. At least one absorber member is disposed onor around the ultrasound transmission wire at a location adjacent thesonic connector of the catheter. The absorber member absorbs heat,vibrations, and/or the like from the ultrasound transmission wire at ornear the area where the transmission wire is coupled with the sonicconnector. The absorptive function typically slows the process of wearand tear on the transmission wire, thus extending the useful life of theultrasound catheter.

In one aspect of the invention, an ultrasound catheter for disruptingocclusions in blood vessels comprises: an elongate flexible catheterbody having a proximal end, a distal end and at least one lumen; anultrasound transmission member extending longitudinally through thelumen of the catheter body; a sonic connector coupled with a proximalend of the ultrasound transmission member for coupling the ultrasoundtransmission member with a separate ultrasound generating device; and atleast one heat absorbing member coupled with the ultrasound transmissionmember adjacent the sonic connector. In some embodiments, the heatabsorbing member surrounds a portion of the ultrasound transmissionmember adjacent a distal end of the sonic connector. Optionally, theheat absorbing member includes a bore for receiving the ultrasoundtransmission member. In some embodiments, such a heat absorbing memberis tubular.

In some embodiments, the heat absorbing member contacts a distal end ofthe sonic connector, while in other embodiments the heat absorbingmember may be separated from a distal end of the sonic connector by adistance of a few millimeters. The heat absorbing member may compriseone piece or, in other embodiments, the heat absorbing member maycomprise at least two component parts such as at least one absorptivepart in contact with the transmission member for absorbing heat and atleast one constraining part coupled with the absorptive part for holdingthe absorptive part in place on the transmission member. In some suchembodiments, the constraining part contacts the transmission member andcomprises at least one absorptive material for absorbing heat. Invarious embodiments, the constraining part may either contact a portionof the sonic connector or overlap a portion of the sonic connector.Optionally, at least one of the absorptive part and the constrainingpart may be capable of absorbing vibrations. In some embodiments, theconstraining part comprises a bore for receiving the ultrasoundtransmission wire, wherein the bore includes a widened portion forreceiving the absorptive part. In some embodiments, the constrainingpart is tubular. Also in some embodiments, the constraining part iscoupled with at least one of the absorptive part and the ultrasoundtransmission wire by at least one of crimping, bonding, fusing orwelding.

In other embodiments, the heat absorbing member comprises at least twocomponent parts comprising at least one vibration absorptive part incontact with the transmission member for absorbing vibrations and atleast one constraining part coupled with the absorptive part for holdingthe absorptive part in place on the transmission member and forabsorbing heat. In some embodiments, the constraining part contacts aportion of the sonic connector, while in other embodiments it overlaps aportion of the sonic connector. In some embodiments, the constrainingpart comprises a bore for receiving the ultrasound transmission wire,wherein the bore includes a widened portion for receiving the absorptivepart. In such embodiments, the constraining part may sometimes betubular.

In some embodiments, the heat absorbing member is capable of absorbingvibrations. In other embodiments, the ultrasound catheter furtherincludes a vibrational absorbing member coupled with the ultrasoundtransmission member for absorbing vibrations. In either case, the heatabsorbing member may comprise at least one metal having heatconductivity properties. The metal(s) may include, but are not limitedto, aluminum and its alloys, titanium and its alloys, and/or magnesiumand its alloys. Finally, in some embodiments the heat absorbing memberis coupled with the ultrasound transmission wire by at least one ofcrimping, bonding, fusing or welding.

In another aspect, an ultrasound catheter for disrupting occlusions inblood vessels includes: an elongate flexible catheter body having aproximal end, a distal end and at least one lumen; an ultrasoundtransmission member extending longitudinally through the lumen of thecatheter body; a sonic connector coupled with a proximal end of theultrasound transmission member for coupling the ultrasound transmissionmember with a separate ultrasound generating device; and at least onevibration absorbing member coupled with the ultrasound transmissionmember adjacent the sonic connector. Any of the features andcombinations described for the embodiments above may be equally appliedto this aspect of the invention.

In some embodiments, the vibration absorbing member surrounds a portionof the ultrasound transmission member adjacent a distal end of the sonicconnector. For example, the vibration absorbing member may include abore for receiving the ultrasound transmission member. In someembodiments, the vibration absorbing member is tubular. In someembodiments, the vibration absorbing member contacts a distal end of thesonic connector, while in others it is separated from a distal end ofthe sonic connector by a distance of a few millimeters. For example, insome embodiments, the absorbing member may be separated from the sonicconnector by approximately ¼ of a wavelength produced by the ultrasounddevice.

In some embodiments, the vibration absorbing member comprises at leasttwo component parts, the component parts comprising: at least oneabsorptive part in contact with the transmission member for absorbingvibrations; and at least one constraining part coupled with theabsorptive part for holding the absorptive part in place on thetransmission member. In some embodiments, the at least one constrainingpart contacts the transmission member and comprises at least oneabsorptive material for absorbing heat. Also in some embodiments, the atleast one constraining part contacts or overlaps a portion of the sonicconnector. In some embodiments, at least one of the absorptive part andthe constraining part is capable of absorbing heat. In some embodiments,the at least one constraining part comprises a bore for receiving theultrasound transmission wire, wherein the bore includes a widenedportion for receiving the absorptive part. In such embodiments, theconstraining part may be tubular. The constraining part may be coupledwith at least one of the absorptive part and the ultrasound transmissionwire by at least one of crimping, bonding, fusing or welding.

In other embodiments, the vibration absorbing member comprises at leasttwo component parts, the component parts comprising: at least onevibration absorptive part in contact with the transmission member forabsorbing vibrations; and at least one constraining part coupled withthe absorptive part for holding the absorptive part in place on thetransmission member and for absorbing heat. The at least oneconstraining part may contact or overlap a portion of the sonicconnector in various embodiments. Optionally, the constraining part mayinclude a bore for receiving the ultrasound transmission wire, whereinthe bore includes a widened portion for receiving the absorptive part.In such embodiments, the constraining part may be tubular, for example.

In some embodiments, the vibration absorbing member is capable ofabsorbing heat. In other embodiments, the ultrasound catheter furtherincludes a heat absorbing member coupled with the ultrasoundtransmission member for absorbing heat. In some embodiments thevibration absorbing member comprises at least one vibration absorbingmaterial selected from the group consisting of rubbers and polymers. Insome embodiments, the vibration absorbing member further comprises atleast one metal having heat conductivity properties. For example, such ametal may be selected from the group consisting of aluminum, titanium,and magnesium. In some embodiments, the vibration absorbing member iscoupled with the ultrasound transmission wire by at least one ofcrimping, bonding, fusing or welding.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an ultrasound catheter systemconstructed according to the principles of the present invention.

FIG. 2 is a cross-sectional view of an ultrasound catheter having anabsorber member according to an embodiment of the present invention.

FIG. 3A is a magnified view of a proximal end of an ultrasound catheteras shown in FIG. 2.

FIG. 3B is a further magnified view of a proximal end of an ultrasoundcatheter as shown in FIGS. 2 and 3A.

FIGS. 4A-4C are cross-sectional views of proximal ends of ultrasoundcatheters having absorber members according to various embodiments ofthe invention.

DETAILED DESCRIPTION OF THE INVENTION

Ultrasound catheter devices and methods of the present inventiongenerally provide for ablation and/or disruption of vascular occlusions.An ultrasound transmission member, such as a wire, transmits vibrationalenergy from an ultrasound transducer to a distal head of the catheter todisrupt vascular occlusions. At least one absorber member is disposed onor around the ultrasound transmission wire at a location adjacent thesonic connector of the catheter. The absorber member absorbs heat,vibrations, and/or the like from the ultrasound transmission wire at ornear the area where the transmission wire is coupled with the sonicconnector. The absorptive function typically slows the process of wearand tear on the transmission wire, thus extending the useful life of theultrasound catheter. Although catheters of the invention are describedin detail below, for further details reference may be made to U.S.patent application Ser. No. 10/229,371, filed Aug. 26, 2002, which waspreviously incorporated by reference.

Referring now to FIG. 1, one embodiment of an over-the-wire ultrasoundcatheter system 20 suitably includes an ultrasound catheter 10, aproximal end connector assembly 12 coupled with catheter 10, anultrasound transducer 14 coupled with the proximal end of proximalconnector assembly 12, and an ultrasound generator 16 with afoot-actuated on/off switch 18, which is operatively coupled withultrasound transducer 14 to provide ultrasonic energy to transducer 14and, thus, to ultrasound catheter 10. Generally, catheter 10 willinclude an ultrasound transmission member, or wire (not shown), fortransmitting energy from the transducer 14 to a distal head 26 of thecatheter. Proximal connector assembly 12, described more fully below,may have a Y-connector 15 with one or more side-arms 13, for example forproviding irrigation fluid via an irrigation tube 11. The catheter 10may be passed along a guide wire 17 which accesses catheter 10 via aside aperture. The side aperture may be located close to the distal endof catheter 10 or in another embodiment (not shown) close to theproximal end of catheter 10.

Ultrasound catheters 10 of the present invention may be used with anysuitable combination of devices, such as any suitable ultrasoundtransducer 14, ultrasound generator 16, and/or the like. Therefore,exemplary FIG. 1 and any following descriptions of ultrasound catheterapparatus or systems should in no way be interpreted to limit the scopeof the present invention as defined in the appended claims. Again,exemplary ultrasound catheters which may incorporate one or moreimprovements of the present invention are described in previouslyincorporated U.S. patent application Ser. No. 10/229,371. Otherexemplary catheters are described in U.S. patent application Ser. No.10/345,078, filed on Jan. 14, 2003, entitled “Ultrasound Catheter andMethods for Making and Using Same,” by an inventor of the presentinvention, the full disclosure of which is hereby incorporated byreference. On the other hand, any suitable ultrasound catheter now knownor hereafter discovered may be configured to include one or moreimprovements of the present invention and, thereby, fall within thescope of the invention.

Referring now to FIGS. 2 and 3, cross-sectional side views of ultrasoundcatheter 10 and a proximal portion of ultrasound catheter 10 are shown,respectively. Generally, ultrasound catheter 10 suitably includes anelongate catheter body 22 with an ultrasound transmission member 24disposed longitudinally through its lumen and ending in distal head 26.Catheter body 22 is generally a flexible, tubular, elongate member,having any suitable diameter and length for reaching a vascularocclusion for treatment. In one embodiment, for example, catheter body22 preferably has an outer diameter of between about 0.5 mm and about5.0 mm. In other embodiments, as in catheters intended for use inrelatively small vessels, catheter body 22 may have an outer diameter ofbetween about 0.25 mm and about 2.5 mm. Catheter body 22 may also haveany suitable length. As discussed briefly above, for example, someultrasound catheters have a length in the range of about 150 cm.However, any other suitable length may be used without departing fromthe scope of the present invention. Examples of catheter bodies similarto those which may be used in the present invention are described inU.S. Pat. Nos. 5,267,954 and 5,989,208, which were previouslyincorporated herein by reference.

In most embodiments, ultrasound transmission member 24, wire, or waveguide extends longitudinally through catheter body lumen 21 to transmitultrasonic energy from ultrasound transducer 14, connected to theproximal end of catheter 10, to the distal end of catheter 10.Ultrasound transmission member 24 may be formed of any material capableof effectively transmitting ultrasonic energy from ultrasound transducer14 to the distal end of catheter body 22, including but not limited tometals such as pure titanium or aluminum, or titanium or aluminumalloys.

In accordance with one aspect of the invention, all or a portion ofultrasound transmission member 24 may be formed of one or more materialswhich exhibit superelastic properties. Such material(s) shouldpreferably exhibit superelasticity consistently within the range oftemperatures normally encountered by ultrasound transmission member 24during operation of ultrasound catheter apparatus 10. Specifically, allor part of the ultrasound transmission member 24 may be formed of one ormore metal alloys known as “shape memory alloys.”

Use of supereleastic metal alloys in ultrasound transmission members isdescribed in U.S. Pat. No. 5,267,954, previously incorporated byreference. Examples of superelastic metal alloys which may be used aredescribed in detail in U.S. Pat. Nos. 4,665,906 (Jervis); 4,565,589(Harrison); 4,505,767 (Quin); and 4,337,090 (Harrison). The disclosuresof U.S. Pat. Nos. 4,665,906; 4,565,589; 4,505,767; and 4,337,090 areexpressly incorporated herein by reference insofar as they describe thecompositions, properties, chemistries and behavior of specific metalalloys which are superelastic within the temperature range at which theultrasound transmission member of the present invention operates, anyand all of which superelastic metal alloys may be used to formultrasound transmission member 24 of the present invention.

In many embodiments, ultrasound transmission member 24 includes one ormore tapered regions along a portion of its length, towards its distalend. Such a tapered region decreases the distal rigidity of ultrasoundtransmission member 24, thus amplifying ultrasound energy transmittedalong ultrasound transmission member 24 to distal head 26. The taperedregion typically divides the transmission member 24 between a proximalportion and a distal portion, which both typically have a largercross-sectional diameter than the tapered region. A thicker distalportion, for example, may enhance stability of the connection betweenultrasound transmission member 24 and distal head 26. Other embodimentsare contemplated, however. For example, the tapered region may bepositioned at the extreme distal end of transmission member 24. In stillother embodiments, ultrasound transmission member 24 may includemultiple tapered portions, widened portions and/or the like. Thus,ultrasound transmission member 24 may be configured with any suitablelength, combinations of diameters and tapers, or any other suitableshapes, sizes or configurations to advantageously transmit ultrasoundenergy from transducer 14 to distal tip 26.

In some embodiments ultrasound transmission member 24 may include alow-friction coating or jacket on all or a portion of its outer surface.The coating may be disposed on the outer surface of ultrasoundtransmission member 24 so as to completely cover ultrasound transmissionmember 24 along its entire length, or along a discrete region or regionsthereof. Such a coating or jacket may comprise a layer of low frictionpolymer material such as polytetrafluoroethylene (PTFE), TEFLON™(available from DUPONT, INC., Wilmington, Del.) or other plasticmaterials such as polyethylene. The coating may be applied as a liquidand subsequently allowed to cure or harden on the surface of ultrasoundtransmission member 24. Alternatively, the coating may be in the form ofan elongate tube, disposable over the outer surface of ultrasoundtransmission member 24. Generally, the coating serves to prevent ordiminish friction between the outer surface of ultrasound transmissionmember 24 and the adjacent structures of catheter 10 or proximal endconnector assembly 12 through which ultrasound transmission member 24extends.

With continued reference to FIGS. 2 and 3A, one embodiment of proximalend connector assembly 12 suitably includes a housing 42 with a hollowinner bore 44. Bore 44 may have a uniform inner diameter along itslength or, alternatively, may have multiple segments, such as a proximalsegment 47, a middle segment 45 and a distal segment 49, each of whichmay surround one or more various components of proximal end connectorapparatus 12. Generally, proximal segment 47 of bore 44 is configured toallow coupling with ultrasound transducer 14 (not shown) via anysuitable coupling means, such as a pressure fit, complementary threadsor the like. Proximal segment 47 includes a sonic connector 52 fortransmitting vibrational energy from transducer 14 to ultrasoundtransmission member 24. In some embodiments, sonic connector 52 may beheld within housing 42, by means of dowel pin 53. In other embodiments,dowel pin 53 may not be included and sonic connector 52 may bepositioned within housing 42 by other means.

Middle segment 45 of bore 44, in some embodiments, may surround aportion of sonic connector 52, while in other embodiments, sonicconnector 52 may be housed only within proximal segment 47. Sonicconnector 48 is coupled with the distal end of ultrasound transmissionmember 24 by any suitable means for transmitting ultrasound energy totransmission member 24 from transducer 14. An absorber member 50 isdisposed around at least a portion of ultrasound transmission member 24immediately distal and immediately adjacent to sonic connector 52.Absorber member 50 is described in further detail below, but generallyis configured to abut sonic connector 52 to absorb heat and/ortransverse vibrations from, and therefore reduce wear and tear on,ultrasound transmission member 24. Optionally, some embodiments furtherinclude one or more O-rings 46 distal to absorber member 50 and disposedabout ultrasound transmission member 24 for providing further absorptionof transverse vibration. Absorber member 50 and O-rings 46 may be usedin any number or combination and have and suitable size andconfiguration, depending on the desired level of vibration absorption ordampening. Alternatively or additionally, other dampening structures maybe used. Thus, the invention is not limited to the combination shown inFIG. 2.

Distal segment 49 of bore 44 typically surrounds a portion of ultrasoundtransmission member 24 and may also contain one or more additional setsof absorber members 46. Distal segment 49 may also contain a portion ofa Y-connector 15, which is coupled with the distal end 43 of housing 42of proximal end connector apparatus 12. Coupling of Y-connector 15 withdistal end 43 of proximal end connector assembly 12 may be accomplishedvia complementary threads, pressure fitting, or any other suitablemeans. A Y-connector lumen 48 of Y-connector 15 allows passage ofultrasound transmission member 24 and is in communication with thecatheter body lumen.

Generally, pressurized fluid such as a coolant liquid may be infusedthrough side-arm 13, through Y-connector lumen 45 and through thecatheter body lumen so that it flows out of one or more fluid outflowapertures in distal head. The temperature and flow rate of such coolantliquid may be specifically controlled to maintain the temperature ofultrasound transmission member 24 at a desired temperature within itsoptimal working range. In particular, in embodiments of the inventionwherein ultrasound transmission member 24 is formed of a metal alloywhich exhibits optimal physical properties (e.g. super elasticity)within a specific range of temperatures, the temperature and flow rateof coolant liquid infused through fluid infusion side-arm 13 may bespecifically controlled to maintain the temperature of ultrasoundtransmission member 24 within a range of temperatures at which itdemonstrates its most desirable physical properties. For example, inembodiments of the invention wherein ultrasound transmission member 24is formed of a shape memory alloy which exhibits super elasticity whenin its martensite state, but which loses super elasticity as ittransitions to an austenite state, it will be desirable to adjust thetemperature and flow rate of the coolant liquid infused through fluidinfusion side-arm 13 so as to maintain the shape memory alloy ofultrasound transmission member 24 within a temperature range at whichthe alloy will remain in its martensite state and will not transition toan austenite state. The temperature at which such shape memory alloystransition from a martensite state to an austenite state is known as the“martensite transition temperature” of the material. Thus, in theseembodiments, the fluid infused through side-arm 13 will be at suchtemperature, and will be infused at such rate, as to maintain the shapememory alloy of ultrasound transmission member 24 below its martensitetransition temperature.

Referring to FIGS. 3A and 3B, one embodiment of absorber member 50 ofthe present invention is shown disposed about ultrasound transmissionwire 24 and immediately adjacent the distal end of sonic connector 52.Generally, absorber member 50 may have any suitable size, shape orconfiguration, may be made of any suitable material, and may be coupledwith ultrasound transmission member 24 by any suitable means to providefor absorption or dampening of heat, transverse vibrations, otherunwanted stresses on ultrasound transmission member 24 and/or the like.Typically, absorber member 50 is made from relatively light-weightmaterial(s), so that little or no additional load is placed on thetransmission wire. In some embodiments, absorber member 50 comprises oneor more materials having heat transfer properties for absorbing heatfrom ultrasound transmission member 24. Essentially, such an absorbermember 50 acts as a heat sink to help prevent ultrasound transmissionmember from increasing in temperature to a level which may increase wearand tear of transmission member 24. Materials which may be used forproviding absorber member with heat absorption properties, for example,may include but are not limited to aluminum and its alloys, magnesiumand it alloys and/or titanium and its alloys.

Absorber member 50 may be coupled with ultrasound transmission member 24by any suitable means. In some embodiments, for example, absorber member50 may be positioned at a desired location on transmission member 24during manufacturing and then may be crimped, using a crimping device,to adhere to transmission member 24. Other methods for coupling absorbermember 50 with transmission member 24 are also contemplated, such aspressure fitting, use of adhesive substances, and the like.

Absorber members 50 of the present invention are generally positioned ontransmission member 24 at a location adjacent to the distal end of sonicconnector 52. As shown in FIG. 3A, in some embodiments absorber member50 is positioned immediately adjacent and abutting the distal end ofsonic connector 52. In other embodiments, as in FIG. 3B, absorber member50 may be disposed very close to the distal end of sonic connector 52without actually abutting or touching sonic connector 52. In variousembodiments, for example, the distance between the distal end of sonicconnector 52 and the proximal end of absorber member 50 may range up toa few millimeters.

With reference now to FIGS. 4A and 4C, various embodiments of proximalend connector apparatus 12 may include an absorber member 50 having twoor more component parts and/or comprising two or more differentmaterials. For example, in some embodiments absorber member 50 includesa vibrational absorber 58 immediately surrounding transmission member 24and a constraining member 56 immediately surrounding vibrationalabsorber 58. In various embodiments, vibrational absorber 58 and/orconstraining member 56 may be configured to absorb transversevibrations, absorb/transfer heat, or both. In some embodiments, forexample, vibrational absorber 58 is made from a polymer or plasticcapable of absorbing both vibrations and heat, while constraining member56 is configured primarily to hold vibrational absorber 58 in place ontransmission member 24.

In other embodiments, for example as in FIG. 4B, a differently shapedconstraining member 64 may include one or more heat absorptivematerials, and part of constraining member 64 may contact transmissionmember 24 or be disposed in close proximity to transmission member 24 toabsorb heat generated in transmission member 24. Constraining member 64may also absorb vibrations in some embodiments. In various embodiments,therefore, constraining member 56, 64 may serve a constraining function,a vibrational absorption function, a heat absorption function, or anycombination thereof.

Referring now to FIG. 4C, another embodiment of absorber member 50includes a constraining member 68 that overlaps a distal portion ofsonic connector 52. Again, such a constraining member 68 may provide forvibration and/or heat absorption in addition to the constrainingfunction. In such overlapping embodiments, vibrational absorber 58 maydirectly abut the distal end of sonic connector 52 or may be spacedapart from sonic connector 52, as shown in FIG. 4C. Generally, absorbermembers 50 of the invention will include at least one part that abuts oris closely adjacent to sonic connector 52, but may include one or moreparts that are separate as well, as in FIG. 4C. As is evident from FIGS.4A-4C, absorber member 50 may include any suitable combination ofcomponent parts having any suitable configuration and comprising anysuitable combination of materials. In other embodiments, of course,absorber member 50 may comprise one, unitary piece, may comprise morethan two components parts, or the like.

Although the invention has been described above with specific referenceto various embodiments and examples, it should be understood thatvarious additions, modifications, deletions and alterations may be madeto such embodiments without departing from the spirit or scope of theinvention. Accordingly, it is intended that all reasonably foreseeableadditions, deletions, alterations and modifications be included withinthe scope of the invention as defined in the following claims.

1. An ultrasound catheter for disrupting occlusions in blood vessels, the ultrasonic catheter comprising: an elongate flexible catheter body having a proximal end, a distal end and at least one lumen; an ultrasound transmission member extending longitudinally through the lumen of the catheter body; a sonic connector coupled with a proximal end of the ultrasound transmission member for coupling the ultrasound transmission member with a separate ultrasound generating device; and at least one vibration absorbing member coupled with the ultrasound transmission member adjacent the sonic connector.
 2. An ultrasound catheter as in claim 1, wherein the vibration absorbing member surrounds a portion of the ultrasound transmission member adjacent a distal end of the sonic connector.
 3. An ultrasound catheter as in claim 2, wherein the vibration absorbing member includes a bore for receiving the ultrasound transmission member.
 4. An ultrasound catheter as in claim 3, wherein the vibration absorbing member is tubular.
 5. An ultrasound catheter as in claim 1, wherein the vibration absorbing member contacts a distal end of the sonic connector.
 6. An ultrasound catheter as in claim 1, wherein the vibration absorbing member is separated from a distal end of the sonic connector by a distance of approximately ¼ wavelength of an ultrasound wave transmitted to the ultrasound catheter.
 7. An ultrasound catheter as in claim 1, wherein the vibration absorbing member comprises at least two component parts, the component parts comprising: at least one absorptive part in contact with the transmission member for absorbing vibrations; and at least one constraining part coupled with the absorptive part for holding the absorptive part in place on the transmission member.
 8. An ultrasound catheter as in claim 7, wherein the at least one constraining part contacts the transmission member and comprises at least one absorptive material for absorbing heat.
 9. An ultrasound catheter as in claim 8, wherein the at least one constraining part contacts a portion of the sonic connector.
 10. An ultrasound catheter as in claim 8, wherein the at least one constraining part overlaps a portion of the sonic connector.
 11. An ultrasound catheter as in claim 7, wherein at least one of the absorptive part and the constraining part is capable of absorbing heat.
 12. An ultrasound catheter as in claim 7, wherein the at least one constraining part comprises a bore for receiving the ultrasound transmission wire, wherein the bore includes a widened portion for receiving the absorptive part.
 13. An ultrasound catheter as in claim 12, wherein the constraining part is tubular.
 14. An ultrasound catheter as in claim 12, wherein the constraining part is coupled with at least one of the absorptive part and the ultrasound transmission wire by at least one of crimping, bonding, fusing or welding.
 15. An ultrasound catheter as in claim 1, wherein the vibration absorbing member comprises at least two component parts, the component parts comprising: at least one vibration absorptive part in contact with the transmission member for absorbing vibrations; and at least one constraining part coupled with the absorptive part for holding the absorptive part in place on the transmission member and for absorbing heat.
 16. An ultrasound catheter as in claim 15, wherein the at least one constraining part contacts a portion of the sonic connector.
 17. An ultrasound catheter as in claim 15, wherein the at least one constraining part overlaps a portion of the sonic connector.
 18. An ultrasound catheter as in claim 15, wherein the at least one constraining part comprises a bore for receiving the ultrasound transmission wire, wherein the bore includes a widened portion for receiving the absorptive part.
 19. An ultrasound catheter as in claim 18, wherein the constraining part is tubular.
 20. An ultrasound catheter as in claim 1, wherein the vibration absorbing member is capable of absorbing heat.
 21. An ultrasound catheter as in claim 1, further comprising a heat absorbing member coupled with the ultrasound transmission member for absorbing heat.
 22. An ultrasound catheter as in claim 1, wherein the vibration absorbing member comprises at least one vibration absorbing material selected from the group consisting of a rubber, a polymer, and a rubber/polymer combination.
 23. An ultrasound catheter as in claim 22, wherein the vibration absorbing member further comprises at least one metal having heat conductivity properties.
 24. An ultrasound catheter as in claim 23, wherein the at least one metal is selected from the group consisting of aluminum, aluminum alloys, titanium, titanium alloys, magnesium, and magnesium alloys.
 25. An ultrasound catheter as in claim 1, wherein the vibration absorbing member is coupled with the ultrasound transmission wire by at least one of crimping, bonding, fusing or welding. 